Data is beautiful: Mapping The World's Tweet Networks @enf
This is a picture of the world, as connected by Twitter created by Eric Fischer @enf and shows people's virtual and physical networks It shows where people travel--and, what's more, who they communicate with all around the world. Thus, in one map, you can see where people's physical communities are, and their virtual ones as well.
There are a load more of this here with some explanation http://www.fastcodesign.com/1665780/infographic-of-the-day-mapping-the-worlds-tweet-networks